Case IH 6584-01 - DEC – Electronic Transmission Controller (ETC) / Transmission Control Unit (TCU): Transmission Hydrostatic Loop 2 Pressure - Data Valid But Below Normal Operational Range

The system has detected that the hydrostatic pressure in Loop B (Loop 2) of the transmission has dropped below the minimum safe operating threshold. This indicates a potential loss of hydrostatic drive pressure, which could be caused by a failing hydrostatic pump, a severe internal/external fluid leak, critically low transmission fluid, or a faulty pressure sensor.

• MAGNUM AFS Connect
• Magnum CVXDrive
• Puma CVXDrive
• Maxxum CVXDrive
• Steiger CVXDrive
• combine harvesters
• self-propelled sprayers

1. 1

   Fluid Level Check: Verify the transmission/hydraulic fluid level is within the normal operating range. Low fluid can cause a sudden drop in loop pressure.

2. 2

   Visual Inspection: Inspect the transmission housing, hydrostatic pump, and hydraulic lines for any signs of external fluid leaks.

3. 3

   Sensor and Wiring Inspection: Locate the Hydrostatic Loop B (Loop 2) pressure sensor. Inspect the sensor connector and wiring harness for corrosion, bent pins, chafing, or open/short circuits.

4. 4

   Manual Pressure Test: Install a mechanical pressure gauge on the transmission's Loop B diagnostic port. Compare the mechanical gauge reading to the pressure value being reported by the sensor via the diagnostic service tool. If the mechanical gauge shows normal pressure but the sensor reads low, the sensor or wiring is faulty. If the mechanical gauge confirms the pressure is actually below normal, there is a mechanical or hydraulic failure.

1. 1

   Prepare machine

   Park the machine on a level surface, engage the parking brake, and turn off the engine. Relieve any residual hydraulic pressure.

2. 2

   Replace sensor (if faulty)

   If the diagnostic checks point to a faulty sensor: Disconnect the electrical harness from the Hydrostatic Loop B pressure sensor. Unthread and remove the faulty pressure sensor from the transmission housing/valve block. Install the new pressure sensor with a new O-ring/seal, tightening to the OEM torque specification. Reconnect the electrical harness.

3. 3

   Top off fluid and repair leaks (if low fluid)

   If the diagnostic checks point to low fluid: Top off the transmission reservoir with the approved Case IH hydraulic/transmission fluid. Repair any external leaks found during the visual inspection.

4. 4

   Overhaul hydrostatic unit (if mechanical failure)

   If the diagnostic checks confirm actual low hydrostatic pressure (mechanical failure): The transmission or hydrostatic drive unit will require a deeper teardown to inspect the hydrostatic pump, motor, and internal seals. This typically requires splitting the tractor or removing the hydrostatic unit for a complete overhaul.

5. 5

   Clear codes and test

   Clear the fault codes using the electronic service tool and test drive the machine under load to verify the pressure remains in the normal range and the code does not return.